The present invention relates to an automatic surveillance, guidance and fire-fighting system or installation, and concerns a system or installation whose primary purpose is to prevent accidents and, in the event that they do occur due for example to aircraft fault or pilot error, to bring about the extinction of any fires which occur, in the shortest possible time, by means of the functional integration of surface telemetry and automated fire-fighting.
In the same way that other airport systems were designed and implemented in their time (such as VASIS, ILS, CALVERT, etc.), all of which satisfactorily met the established requirements for achieving air safety, so also the present, newly designed system (RUSTEM), meets other requirements in the same field, but within the airport precincts.
In order to explain what the system comprises as well as the grounds which justify it, it is useful to set out the current state of affairs and accordingly introduce the necessary conceptual innovation in specific important aspects, being those which epitomize the characteristics of RUSTEM ("Runway Security and Taxiway Escort System").
In effect, wherever there is an aircraft in operation, the concept of air safety and the necessary means of attaining this must be present, whether the aircraft is in the air or on the ground Thus the concept of air safety covers the whole range of air-air, air-ground, ground-ground and ground-air circumstances.
Likewise, if this approach is not taken, a gap in safety will occur in this relationship which may result in an accident, whilst the aircraft is in operation in any of the four circumstances mentioned above, transporting people, goods and fuel.
It is well-known in the air industry that from time to time serious accidents occur, although their prevention, and where necessary fire-fighting operations, have been a priority effort of the aeronautical profession. The present system is part of this effort, though in this instance it is related to the airport environment, that is the ground-ground situation.
In this context it is appropriate to recall the accident which occurred in 1983 at the airport of Barajas (Madrid), in which two aircraft collided on the ground. On this occasion, one aircraft was on its take-off run, whilst the other aircraft in taxiing and trying to head for the start of the runway to take-off in its turn, took a wrong turning and moving across a fast exit slipped into the middle of the flight path, where the collision occurred.
At this time the airport was not under minimums, but visibility was poor so that the aircraft which was taking off did not see the intruding aircraft, neither did the latter see the aircraft taking off, nor did the tower at that time see either of the aircraft, all due to the length of the runways This occurs in certain circumstances where the airport is operative but there is not clear visibility over the full distances.
These situations, and many others, indicate conditions of a lack of air safety which require analysis and a complete solution of the problems to which they give rise.
Furthermore, an aircraft in flight is not close to the ground, whilst in take-offs, landings and taxiing, it is in contact with it and therefore is in a higher risk situation, in which safety conditions must be maximized.
Since it is possible to set up ground installations in airports which could not be set up throughout a country, and since aircraft must operate in airports, it is clearly desirable to provide a safety system on runways and taxiways capable of guaranteeing this safety. The RUSTEM system is intended to meet this requirement.
Also, the increase in modern air traffic, which leads at times to saturation in the number of operations per hour on an operative runway, has led to an increase in the risk of accidents, taking into account the poor visibility conditions which often occur. This expansion in traffic makes a built-in airport safety system increasingly urgent and necessary, as the accidents in different airports of the world confirm. The same problem occurs in military air bases, where there is the additional problem that combat aircraft may enter the base in emergency conditions, for which reason telemetric monitoring and automated fire-fighting thus become necessary. The RUSTEM system can be applied to both civil and military airport ground situations.
Two damaging effects occur in an accident: ruptures and fire.
In accidents en route, the most important factor is usually ruptures, whilst generally in airport accidents fire is the cause of the greatest damage.
This is due to the different velocity of the aircraft en route and in the airport, so that the dynamic impact is usually much greater in an accident in the air.
On the other hand, once an accident has taken place in an airport, it is obvious that there is not the least remedy in the case of ruptures, causing damage to the aircraft and the passengers. However, the fire factor develops according to a specific process, and, fire being the determining factor in causing the greatest damage in airport accidents, it may be combatted because it is a process, provided of course that there are the necessary means for this, both in extinguishing capacity and in speed of activation, since without the latter condition the fire itself will put paid to the matter
From what has been said it emerges that the sole means of combatting the rupture factor is by avoiding the accident, as far as possible in the airport, within the present margin of possible aircraft faults or pilot error, for which reason prevention in this case lies in the area of telemetric monitoring, guidance and signalling on the ground. If, despite the measures taken, an accident occurs due to the aircraft or the pilot, the airport infrastructure must then have available an automatic fire-fighting system for eliminating fires extremely rapidly, since fire is generally the most damaging factor in airport accidents.
The research carried cut in the quest for an efficient airport system which will meet these requirements, emphasized the necessity for integrating the surveillance and fire-fighting functions into one single system.
In fact, given the great speed required in fire-fighting, this had to be of an automatic nature. Since an aircraft which has had an accident may become immobilized (or its hot sections) at any point of the surface in question, it was obviously necessary to have available the x,y coordinates of the aircraft or its sections. Hence it was necessary to integrate telemetric surveillance with automated fire-fighting. Furthermore, if surface telemetry provides the x, y position of a damaged aircraft, or of its sections in the case of it being ruptured, this surface telemetry could also be used to obtain the position of normal aircraft, that is not in a state of emergency, in normal operation.
With this, the conclusion was reached that a telemetric method had to be used in our system, both for the monitoring of normal aircraft and for establishing emergencies according to the various forms and circumstances in which these could occur in each instance, as for example fuel which has leaked and is on fire. As aforementioned, the fire-fighting method has to be automatic due to the great speed demanded, since it is not just dealing with a simple fire, but with an aircraft carrying people, and loaded with highly inflammable fuel. Hence the designer's thinking has to be governed by the time-scale, taking the second as the unit.
Nevertheless, it is essential to point out that, regarding air traffic, two very different areas or environments must be considered in airports: on the one hand the flight strips (which contain the flight runways, one runway for each strip), and on the other hand the taxiways in their entirety, and the aircraft parking areas.
The vast majority of airport accidents occur in the first mentioned area, where aircraft are running at great speed. In the second area, in the taxiways, aircraft are travelling slowly in procession and able to brake quickly where necessary, as is the case in the parking areas.
This qualitative and quantitative distinction is taken into account in the present system, supplying the appropriate solution for the characteristics of each of the indicated environments.
As will be seen, the current situation is analysed and, as a result of the limitations of tanker trucks (as currently used in fire-fighting), as well as the limitations of surface radar (as used in surveillance in some airports), research into a new system which could completely solve these limitations, gave rise to the RUSTEM system, in which surveillance and fire-fighting are functionally integrated in a single operational system, constituting an innovation in the airport field.